3D PRESTACK DEPTH MIGRATION IN THE GULF OF SUEZ: A CASE HISTORY¹

Seismic reflection data in the southern Gulf of Suez, offshore Egypt, are commonly severely affected by shallow velocity inhomogeneities in the form of diapiric salt bodies, and depth migration techniques must be used in order to image the presalt structure correctly. Frequently the diapir and the underlying prospective structure are three dimensional rather than two dimensional and thus require 3D techniques to resolve them. In addition, the severity of the problem is sometimes such that the common midpoint (CMP) stack assumptions are invalid and prestack depth migration is therefore required.

In 1990, Unocal developed a practical 3D prestack depth‐migration scheme, which was applied to a data set in the Gulf of Suez. The prospect was subsequently drilled and results proved the effectiveness of the technique.

This paper describes the use of the technique in the form of a case history. It is expected that the technique will be routinely used to solve similar problems.